A power conditioning system with a fuel cell is known in which output power of the fuel cell can be supplied to a load connected to the fuel cell by supplying fuel gas (e.g. hydrogen) and oxidant gas (e.g. air) to the fuel cell according to a request of the load.
In the power conditioning system as described above, a high-pressure battery (hereinafter, referred to as a “battery”) is provided in parallel with the fuel cell with respect to the load. To synchronize (link) an output voltage of the fuel cell and an output voltage of the battery, a twin converter method is known by which a DC/DC converter for converting an output voltage at a predetermined required voltage ratio is provided on each output side.
In the twin converter method, a control is executed to set an output voltage of the DC/DC converter for battery and an output voltage of the DC/DC converter for fuel cell at a DC link voltage. Here, when the power conditioning system (fuel cell) is started, the DC link voltage is controlled to have a predetermined value by the DC/DC converter for battery.
JP5434197B discloses a control when a fuel cell system with a buck-boost converter for battery is started. In this fuel cell system, an output voltage of a fuel cell is controlled to a high-potential avoiding voltage lower than an open-circuit voltage in consideration of the durability of the fuel cell and the degradation of a battery.